gistfile1.m

- (id)initWithFrame:(CGRect)frame attributedString:(NSAttributedString *)attributedString
{
  self = [super init];
	
	if (self)
	{
		_synchQueue = dispatch_queue_create("DTMutableCoreTextLayoutFrame Sync Queue", DISPATCH_QUEUE_CONCURRENT);
	}
	
	return self;
}

- (void)dealloc
{
#if !OS_OBJECT_USE_OBJC
  dispatch_release(_synchQueue);
#endif
}

- (void)drawInContext:(CGContextRef)context options:(DTCoreTextLayoutFrameDrawingOptions)options
{
  dispatch_sync(_synchQueue, ^{
		[super drawInContext:context options:options];
	});
}


- (void)replaceTextInRange:(NSRange)range withText:(NSAttributedString *)text dirtyRect:(CGRect *)dirtyRect
{
  dispatch_barrier_sync(_synchQueue, ^{
		// updates

	});
}